Ageratum houstonianum ‘Blue Horizon’ is an old-fashioned floss flower with extra height, long bloom, and fluffy lavender-blue flower clusters that are wonderfully pettable. Unlike short bedding types, this tall ageratum grows about 30" high on sturdy branching stems, making it useful for borders, cutting gardens, cottage plantings, and pollinator-friendly annual displays.

From late spring into winter in mild climates, ‘Blue Horizon’ produces rich, soft flower clusters up to 4" across above attractive emerald-green foliage. The airy blooms are excellent in fresh bouquets, where they add cool color and a soft, textural finish. In the garden, they pair beautifully with zinnias, cosmos, marigolds, calendula, salvias, and ornamental grasses.

Plant Ageratum houstonianum ‘Blue Horizon’ in full sun to light shade with rich, well-drained soil and regular water. Deadhead or cut for bouquets to encourage continued bloom. Easy, floriferous, and full of vintage charm, this tall blue floss flower is a lovely way to add soft color for months. Explore more seasonal favorites in our Annuals collection.